1. Technical Field
The invention relates to nanotechnology. In particular, the invention relates to structures having nano-scale feature sizes fabricated using nano-structures.
2. Description of Related Art
Nanotechnology is concerned with the fabrication and application of so-called nano-scale, crystalline structures, structures having at least one linear dimension between 1 nm and 200 nm. These nano-scale crystalline structures are often 50 to 100 times smaller than conventional semiconductor structures. Hereinafter, a nano-scale, crystalline structure may be referred to as a ‘nano-structure’ that includes, but is not limited to, a nanoparticle and a nanowire. Nanoparticles and nanowires are individual, low dimensional, nano-scale, crystalline structures. Specifically, nanoparticles are generally characterized as having three quantum confined dimensions or directions (i.e., width, height, and length) while nanowires typically are characterized as having two quantum confined dimensions or directions (i.e., width and height) along with one unconfined dimension or direction (i.e., length). The presence of the unconfined dimension in nanowires facilitates electrical conduction along that dimension. As such, nanowires may be used in applications requiring true electrical conduction instead of other forms of electron transport such as tunneling. Moreover, the confined and/or unconfined directions provide a specific density of electronic states that may impart significantly different electrical, optical and magnetic properties to nanoparticles and nanowires as well as structures composed thereof when compared to structures comprising more conventional bulk crystalline materials. As such, nanoparticles and nanowires, especially semiconductor nanoparticles and nanowires, offer intriguing possibilities for use in structures comprising aggregated numbers of such nanoparticles or nanowires.
Nano-structures, such as nanoparticles and nanowires may be fabricated by a number of different techniques. For example, nano-structures may be simultaneously fabricated in relatively large quantities and then ‘harvested’ or otherwise collected together as detached or free nano-structures. These free nano-structures may be deposited on a substrate or surface to provide more complex structures composed of many of the nano-structures. For example, nanowires may be deposited on the substrate in a narrow linear cluster made up of a large number of nanowires. Such nanostructure-based, linear clusters may be employed to interconnect circuit elements or components in an integrated circuit, for example, such as a circuit trace or a wire-like interconnect. Alternatively, a large number of nanowires may be deposited on a substrate in a broad planar cluster to form a film or sheet of nanowires (e.g., a nano-layer film). Such nanostructure-based films may be patterned or otherwise modified to become a portion of a circuit element or component (e.g., a gate conductor of a field effect transistor) and/or a portion of a circuit interconnect. Similarly, nanoparticles or combinations of nanowires and nanoparticles may be employed as deposited clusters or aggregations.
Unfortunately, individual nanowires and nanoparticles deposited on a substrate as either a linear, wire-like form or a planar film often exhibit a relatively high aggregate resistivity as a deposited structure. In particular, the aggregate resistivity is often independent of a resistivity of the individual nano-structures that make up the deposited cluster. The high aggregate resistivity is generally due to a relatively small average physical contact area between the individual crystalline nano-structures of the cluster formed during deposition. For example, if a nanowire is assumed to have an essentially cylindrical shape, the physical contact or connectivity between adjacent nanowires, whether the nanowires are deposited with a generally oriented distribution or a generally random or unoriented distribution, is essentially confined to point contacts along a circumference of the nanowires. Such point contacts make for poor electrical as well as mechanical interfaces between deposited nanowires leading to an unexpectedly high aggregate resistance.
Accordingly, it would be desirable to have an approach to create and/or improve connectivity between clusters of nano-structures. Such an approach would solve a long-standing need in the area of nanotechnology and in the use of nano-structures, such as nanowires and nanoparticles.